I was, and still to a certain extent, like that.
Particularly the sight of blood. I could never be a doctor 
I generally now can control it to a certain extent now. I find concentrating very hard on something else (eg saying times tables) can help, as can a drink of water, sitting down, preferably on the floor, or if on a chair, head between the knees.
Signs were similar to "Big", except I also get black patches my sight too.
I always faint in blood tests unless I lie down too.
What I find if one of the dc injures themselves, I can deal with them, get them cleaned up and I then faint. Has caused one or two comedy moments (to look back on).
Pity the young shop assistant in WHSmiths. Dd1 (age about 18 months) hit her nose and very quickly we were both convered with blood. I managed to stop it, and then fainted. Assistant came round the corner to see a mother and child covered in blood (noses hold a lot of blood!) mother out for the count and a toddler crying "mummy wake up"... No wonder they panicked. 